[LU-7138] LBUG: (osd_handler.c:1017:osd_trans_start()) ASSERTION( get_current()->journal_info == ((void *)0) ) failed:

• Type: Bug
• Resolution: Duplicate
• Priority: Blocker
• Affects Version/s: Lustre 2.7.0
• Severity: 1
• Assignee: Oleg Drokin
• Reporter: Frederik Ferner (Inactive)

Description

This evening we have hit this LBUG on the MDT in our production file system, the file system is currently down as we hit the same bug every time we attempt to bring the MDT back, as soon as recovery finishes.

<0>LustreError: 722:0:(osd_handler.c:1017:osd_trans_start()) ASSERTION( get_current()->journal_info == ((void *)0) ) failed:
<0>LustreError: 722:0:(osd_handler.c:1017:osd_trans_start()) LBUG
<4>Pid: 722, comm: mdt01_017
<4>
<4>Call Trace:
<4> [<ffffffffa065f895>] libcfs_debug_dumpstack+0x55/0x80 [libcfs]
<4> [<ffffffffa065fe97>] lbug_with_loc+0x47/0xb0 [libcfs]
<4> [<ffffffffa17df24d>] osd_trans_start+0x25d/0x660 [osd_ldiskfs]
<4> [<ffffffffa09b9b4a>] llog_osd_destroy+0x42a/0xd40 [obdclass]
<4> [<ffffffffa09b2edc>] llog_cat_new_log+0x1ec/0x710 [obdclass]
<4> [<ffffffffa09b350a>] llog_cat_add_rec+0x10a/0x450 [obdclass]
<4> [<ffffffffa09ab1e9>] llog_add+0x89/0x1c0 [obdclass]
<4> [<ffffffffa17f1976>] ? osd_attr_set+0x166/0x460 [osd_ldiskfs]
<4> [<ffffffffa0d914e2>] mdd_changelog_store+0x122/0x290 [mdd]
<4> [<ffffffffa0da4d0c>] mdd_changelog_data_store+0x16c/0x320 [mdd]
<4> [<ffffffffa0dad9b3>] mdd_attr_set+0x12f3/0x1730 [mdd]
<4> [<ffffffffa088a551>] mdt_reint_setattr+0xf81/0x13a0 [mdt]
<4> [<ffffffffa087be1c>] ? mdt_root_squash+0x2c/0x3f0 [mdt]
<4> [<ffffffffa08801dd>] mdt_reint_rec+0x5d/0x200 [mdt]
<4> [<ffffffffa086423b>] mdt_reint_internal+0x4cb/0x7a0 [mdt]
<4> [<ffffffffa08649ab>] mdt_reint+0x6b/0x120 [mdt]
<4> [<ffffffffa0c6f56e>] tgt_request_handle+0x8be/0x1000 [ptlrpc]
<4> [<ffffffffa0c1f5a1>] ptlrpc_main+0xe41/0x1960 [ptlrpc]
<4> [<ffffffff8106c4f0>] ? pick_next_task_fair+0xd0/0x130
<4> [<ffffffffa0c1e760>] ? ptlrpc_main+0x0/0x1960 [ptlrpc]
<4> [<ffffffff8109e66e>] kthread+0x9e/0xc0
<4> [<ffffffff8100c20a>] child_rip+0xa/0x20
<4> [<ffffffff8109e5d0>] ? kthread+0x0/0xc0
<4> [<ffffffff8100c200>] ? child_rip+0x0/0x20
<4>
<0>Kernel panic - not syncing: LBUG

The stack trace doesn't quite seem to be the same as for LU-6634 (which anyway doesn't have any fix suggested.)

Issue Links

• is related to: LU-6556 changelog catalog corruption if all possible records is define
• is related to: LU-6634 (osd_handler.c:901:osd_trans_start()) ASSERTION( get_current()->journal_info == ((void *)0) ) failed: when reaching Catalog full condition

Comments

[Frederik Ferner (Inactive)]

Ok, I've started the build for a Lustre version with the debug patch.

I have a vmcore from the initial LBUG kernel panic, is this potentially useful? (at the moment I'm not sure how I would go about extracting information from this, though.)

[Oleg Drokin]

If you apply a patch like below, it won't really fix anything, but at least we'll know where does the error comes from and what was it (if you have a crashdump from the crash, there's a chance you can extract information from it too).

diff --git a/lustre/obdclass/llog.c b/lustre/obdclass/llog.c
index c34e179..680dae1 100644
--- a/lustre/obdclass/llog.c
+++ b/lustre/obdclass/llog.c
@@ -702,12 +702,16 @@ int llog_write_rec(const struct lu_env *env, struct llog_handle *handle,
 	ENTRY;
 
 	rc = llog_handle2ops(handle, &lop);
-	if (rc)
+	if (rc) {
+		CERROR("llog_handle2ops error %d\n", rc);
 		RETURN(rc);
+	}
 
 	LASSERT(lop);
-	if (lop->lop_write_rec == NULL)
+	if (lop->lop_write_rec == NULL) {
+		CERROR("lop->lop_write_rec == NULL");
 		RETURN(-EOPNOTSUPP);
+	}
 
 	buflen = rec->lrh_len;
 	LASSERT(cfs_size_round(buflen) == buflen);
@@ -718,6 +722,8 @@ int llog_write_rec(const struct lu_env *env, struct llog_handle *handle,
 	rc = lop->lop_write_rec(env, handle, rec, logcookies, idx, th);
 	if (!raised)
 		cfs_cap_lower(CFS_CAP_SYS_RESOURCE);
+	if (rc)
+		CERROR("lop_write_rec error %d\n", rc);
 	RETURN(rc);
 }
 

the patch is only needed on MDS, btw

[Frederik Ferner (Inactive)]

There's nothing obvious in syslog. The full contents of /var/log/messages before the crash/reboot is this:

Sep  7 08:52:49 cs04r-sc-mds03-01 kernel: Lustre: lustre03-MDT0000-osd: FID [0x2000115a3:0x662:0x0] != self_fid [0x200010dc1:0xd167:0x0]
Sep  7 11:25:06 cs04r-sc-mds03-01 kernel: Lustre: lustre03-MDT0000-osd: FID [0x200010dbe:0x9e03:0x0] != self_fid [0x200010dbe:0x9e09:0x0]
Sep  7 12:03:51 cs04r-sc-mds03-01 kernel: Lustre: lustre03-MDT0000-osd: FID [0x200011586:0x283f:0x0] != self_fid [0x200011582:0x41a3:0x0]
Sep  7 13:14:15 cs04r-sc-mds03-01 kernel: Lustre: lustre03-MDT0000-osd: FID [0x200010dab:0x198d5:0x0] != self_fid [0x200011602:0x1c22e:0x0]
Sep  7 13:30:42 cs04r-sc-mds03-01 kernel: Lustre: lustre03-MDT0000-osd: FID [0x200011580:0x9afc:0x0] != self_fid [0x200010da9:0x16251:0x0]
Sep  7 14:10:07 cs04r-sc-mds03-01 kernel: Lustre: lustre03-MDT0000-osd: FID [0x20001157b:0xf7a6:0x0] != self_fid [0x200011581:0x152fe:0x0]
Sep  7 15:47:13 cs04r-sc-mds03-01 kernel: Lustre: lustre03-MDT0000-osd: FID [0x2000115b2:0x4cab:0x0] != self_fid [0x2000115b1:0x4cab:0x0]
Sep  7 18:17:46 cs04r-sc-mds03-01 kernel: Lustre: MGS: Client d6e80b71-1eca-2fca-7854-d8ad02c40814 (at 172.23.116.33@tcp) reconnecting
Sep  7 18:17:46 cs04r-sc-mds03-01 kernel: Lustre: Skipped 1 previous similar message
Sep  7 18:18:46 cs04r-sc-mds03-01 kernel: Lustre: MGS: Client d6e80b71-1eca-2fca-7854-d8ad02c40814 (at 172.23.116.33@tcp) reconnecting
Sep  8 11:05:29 cs04r-sc-mds03-01 kernel: Lustre: lustre03-MDT0000: Client a1185e16-56ed-6244-ef01-edb7c59bbde2 (at 172.23.146.38@tcp) reconnecting
Sep  8 11:05:29 cs04r-sc-mds03-01 kernel: Lustre: Skipped 2 previous similar messages
Sep  8 11:06:11 cs04r-sc-mds03-01 kernel: Lustre: MGS: Client 847ec63e-7411-2e53-d492-aca9e17e6c84 (at 172.23.146.38@tcp) reconnecting
Sep  8 11:06:11 cs04r-sc-mds03-01 kernel: Lustre: Skipped 1 previous similar message
Sep  8 11:06:25 cs04r-sc-mds03-01 kernel: Lustre: lustre03-MDT0000: Client a1185e16-56ed-6244-ef01-edb7c59bbde2 (at 172.23.146.38@tcp) reconnecting
Sep  8 11:07:19 cs04r-sc-mds03-01 kernel: Lustre: lustre03-MDT0000: Client a1185e16-56ed-6244-ef01-edb7c59bbde2 (at 172.23.146.38@tcp) reconnecting
Sep  8 11:07:19 cs04r-sc-mds03-01 kernel: Lustre: Skipped 1 previous similar message
Sep  8 11:11:41 cs04r-sc-mds03-01 kernel: Lustre: MGS: Client 847ec63e-7411-2e53-d492-aca9e17e6c84 (at 172.23.146.38@tcp) reconnecting
Sep  8 11:17:00 cs04r-sc-mds03-01 kernel: Lustre: MGS: Client 847ec63e-7411-2e53-d492-aca9e17e6c84 (at 172.23.146.38@tcp) reconnecting
Sep  8 16:15:16 cs04r-sc-mds03-01 kernel: Lustre: lustre03-MDT0000-osd: FID [0x2000115a4:0xa9e9:0x0] != self_fid [0x200011626:0x1d353:0x0]
Sep  8 17:23:12 cs04r-sc-mds03-01 kernel: Lustre: lustre03-MDT0000: Client a1185e16-56ed-6244-ef01-edb7c59bbde2 (at 172.23.146.38@tcp) reconnecting
Sep  8 17:23:27 cs04r-sc-mds03-01 kernel: Lustre: lustre03-MDT0000: Client a1185e16-56ed-6244-ef01-edb7c59bbde2 (at 172.23.146.38@tcp) reconnecting
Sep  8 18:33:55 cs04r-sc-mds03-01 kernel: Lustre: lustre03-MDT0000-osd: FID [0x200010d9e:0x196cf:0x0] != self_fid [0x20001157c:0x10445:0x0]
Sep  8 20:37:36 cs04r-sc-mds03-01 kernel: Lustre: lustre03-MDT0000-osd: FID [0x20001163d:0x29e3:0x0] != self_fid [0x200010db6:0x1c6f6:0x0]
Sep  9 00:32:12 cs04r-sc-mds03-01 kernel: Lustre: lustre03-MDT0000-osd: FID [0x200011640:0x407d:0x0] != self_fid [0x20001157f:0x1411a:0x0]
Sep  9 01:07:50 cs04r-sc-mds03-01 kernel: Lustre: lustre03-MDT0000: Client a1185e16-56ed-6244-ef01-edb7c59bbde2 (at 172.23.146.38@tcp) reconnecting
Sep  9 02:36:05 cs04r-sc-mds03-01 kernel: Lustre: lustre03-MDT0000-osd: FID [0x2000115bf:0x1b19:0x0] != self_fid [0x200011570:0x1d5c:0x0]
Sep 10 10:21:18 cs04r-sc-mds03-01 kernel: Lustre: lustre03-MDT0000-osd: FID [0x200011645:0x8b5e:0x0] != self_fid [0x20001163a:0xcf49:0x0]
Sep 10 10:29:03 cs04r-sc-mds03-01 kernel: Lustre: lustre03-MDT0000-osd: FID [0x20001163d:0x1dc2d:0x0] != self_fid [0x20001163d:0x1dc37:0x0]
Sep 10 16:48:08 cs04r-sc-mds03-01 kernel: Lustre: lustre03-MDT0000-osd: FID [0x200011668:0x739b:0x0] != self_fid [0x20001167c:0x1501f:0x0]

Mounting the MDT as ldiskfs works and there is lots of space free:

[bnh65367@cs04r-sc-mds03-01 127.0.0.1-2015-09-10-22:05:04]$ df -h
/dev/mapper/vg_lustre03-mgs
                      469M  2.7M  441M   1% /lustre/mgs
/dev/mapper/vg_lustre03-mdt
                      1.5T  103G  1.3T   8% /lustre/lustre03/mdt
[bnh65367@cs04r-sc-mds03-01 127.0.0.1-2015-09-10-22:05:04]$ df -hi
Filesystem           Inodes IUsed IFree IUse% Mounted on
/dev/mapper/vg_lustre03-mdt
                       484M  128M  357M   27% /lustre/lustre03/mdt
/dev/mapper/vg_lustre03-mgs
                       125K   218  125K    1% /lustre/mgs

Is there another option to get the file system back online without the "at your own risk" patch? I'd rather not find out that half written logs are completely trashing our file system...

[Oleg Drokin]

So the next puzzle now is why did llog init or llog write fail, you are not out orf space or anythng like that, are you, no messages in logs pointing at other sources of failures?

You can comment out the llog_destroy call like this as a temporary workaround, though if writes would keep failing, I am sure something else would hit too:

diff --git a/lustre/obdclass/llog_cat.c b/lustre/obdclass/llog_cat.c
index 981af6f..6e51088 100644
--- a/lustre/obdclass/llog_cat.c
+++ b/lustre/obdclass/llog_cat.c
@@ -116,7 +116,7 @@ static int llog_cat_new_log(const struct lu_env *env,
        loghandle->lgh_hdr->llh_cat_idx = rec->lid_hdr.lrh_index;
        RETURN(0);
 out_destroy:
-       llog_destroy(env, loghandle);
+//     llog_destroy(env, loghandle);
        RETURN(rc);
 }

It's also unclear what would happen when the system encounters these half written logs later, so it's really a "try at your own risk" patch.

[Oleg Drokin]

So, looking at the llog_cat_new_log, we can see on error it cleans up with:

out_destroy:
        llog_destroy(env, loghandle);
        RETURN(rc);

This gets translated into llog_osd_destroy that insists it creates its own transaction, but we are already in a transaction which causes thisassertion failure.

It's trivial to reproduce with this patch (Causing 100% cash on startup):

diff --git a/lustre/obdclass/llog_cat.c b/lustre/obdclass/llog_cat.c
index 981af6f..3617e3b 100644
--- a/lustre/obdclass/llog_cat.c
+++ b/lustre/obdclass/llog_cat.c
@@ -105,8 +105,8 @@ static int llog_cat_new_log(const struct lu_env *env,
         * assigned to the record and updated in rec header */
        rc = llog_write_rec(env, cathandle, &rec->lid_hdr,
                            &loghandle->u.phd.phd_cookie, LLOG_NEXT_IDX, th);
-       if (rc < 0)
-               GOTO(out_destroy, rc);
+//     if (rc < 0)
+               GOTO(out_destroy, rc = -5);
 
        CDEBUG(D_OTHER, "new recovery log "DOSTID":%x for index %u of catalog"
               DOSTID"\n", POSTID(&loghandle->lgh_id.lgl_oi),

If we think about it some more - it's actually totally logical that we do not need to cleanup in a different transaction and must cleanup in the same one so that it's atomic in the end.
So I imagine we need to use a different destroy method that would reuse the same transaction.

[Peter Jones]

Oleg is looking into this